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Biomedical subjects

R D Howard

Publications and source records attributed to R D Howard.

At least 37 records · Page 2Linked to original sources
PubMed1984

Dilaceration.

Explore the source record for details and available documents.

Humans↗
PubMed1978

Maxillary anterior displacement and impaction in the mixed dentition.

Attention has been given to problems of eruption in the maxillary anterior region. It is a region where a variety of anomalies occur. Since the maxillary anterior region influences appearance so greatly, early detection of difficulties and careful planning and treatment can be extremely beneficial to patients.

Child↗
PubMedDate not supplied

Arthroscopic subchondral bone plate microfracture technique augments healing of large chondral defects in the radial carpal bone and medial femoral condyle of horses.

OBJECTIVE: To evaluate the effect of arthroscopic subchondral bone microfracture on healing of large chondral defects in horses. STUDY DESIGN: Short- (4 months) and long-term (12 months) in vivo experimental chondral defect model. ANIMALS: 10 horses, aged 2 to 5 years. METHODS: Each horse had a 1 cm2 full-thickness chondral defect created in both radial carpal bones and both medial femoral condyles. One carpus and one femoral condyle of each horse had the subchondral bone plate under the defect perforated using an orthopedic awl. All horses were exercised, five horses were evaluated after 4 months and five horses after 12 months. Gross, histologic, and histomorphometric examination of defect sites and repair tissues was performed, as was collagen typing of the repair tissue. RESULTS: On gross observation a greater volume of repair tissue filled treated defects (74%) compared with control defects (45%). Histomorphometry confirmed more repair tissue filling treated defects, but no difference in the relative amounts of different tissue types was observed. There was an increased percentage of type II collagen in treated defects compared with control defects and evidence of earlier bone remodeling as documented by changes in porosity. CONCLUSIONS: In full-thickness chondral defects in exercised horses, treatment with subchondral bone microfracture increased the tissue volume in the defects and the percentage of type II collagen in the tissue filling the defects when compared to nontreated defects. CLINICAL RELEVANCE: No negative effects of the microfracture technique were observed and some of the beneficial effects are the basis for recommending its use in patients cases with exposed subchondral bone.

Animals↗
PubMedDate not supplied

Arthroscopic anatomy of the equine temporomandibular joint.

OBJECTIVE: To develop an arthroscopic approach to, and describe the arthroscopic anatomy of, the equine temporomandibular joint (TMJ). STUDY DESIGN: Cadaveric study, after which the technique was tested in horses. ANIMALS OR SAMPLE POPULATION: Ten cadaveric equine heads and 5 normal horses (age, 5-13 years; weight, 425-545 kg). METHODS: Specimens or horses were positioned in right lateral recumbency. After fluid distention of the TMJ, arthroscopic portals were made in the dorsal compartment over the most prominent portion of the joint outpouching (caudodorsal approach) and in rostral and intermediate locations. The joint was explored and photographed. Positional changes in the mandible were made to determine if observation of the joint could be improved. Instrument portals were created to assess the feasibility of surgical arthroscopy. Cadaveric heads were dissected to assess iatrogenic damage, whereas experimental horses were observed for postoperative complications for 30 days. RESULTS: A caudodorsal arthroscopic approach provided the best evaluation of the dorsal compartment of the TMJ. The approach allowed observation of the rostral and caudal synovial pouches and the lateral aspect of the joint including the articular disc. Examination of the medial aspect of the joint was limited to the most rostral and caudal aspects. Access to the lateral aspect of the ventral compartment of the TMJ was precluded by the position of the transverse facial artery and vein. In specimens, iatrogenic damage was minimal and limited to the articular fibrocartilage, articular disc, and penetration of the parotid salivary gland. If the latter also occurred in horses, no adverse effects were noted. In horses, mild fluid extravasation occurred and resolved within 1 day. All horses ate normally after surgery but had periarticular swelling and mild pain upon palpation of the TMJ for 2 days. CONCLUSIONS: A caudodorsal arthroscopic approach to the TMJ allowed adequate observation of the lateral aspect of the dorsal compartment of the joint. Access to the ventral compartment was precluded by the location of the transverse facial artery and vein. CLINICAL RELEVANCE: Conditions affecting the lateral and caudal aspects of the dorsal compartment of the TMJ should be visible by arthroscopy.

Animals↗